The Doctor Consults With Wizards
by PondGirl11
Summary: The Doctor is broken after he loses the Ponds. He needs a friend to call on, and it seems that friend is John Watson. He is so grateful to John for taking him in that he grants him one question. The answer will change his life... Doctor Who, Sherlock and The Marauders! Collaboration between me and my friend. Currently on hiatus.
1. Meeting John

**This is a really exciting project for me because it's not only the first time I've written for Sherlock or Harry Potter, but it's also my first crossover and my first joint fanfiction! The chapters will be written as follows: one from me, one from my friend etc. She does not have fanfiction so all chapters will be published on my account only. Just something to remember: this is **_**not**_** linked to **_**any**_** of my other fanfictions, so Ally does not exist in this AU. There **_**may**_** be sequels to this story, but we're not promising anything because we have a storyline worked out but we don't know how long it will be and what the chapter lengths will be. Enjoy, and please excuse the two obviously different styles of writing!**

Sometimes, the Doctor regretted getting involved. When it went wrong, or when people got hurt because of him. It may surprise you to know that sometimes, just sometimes, people got hurt but he didn't regret it. Because it wasn't his fault. Or he made a friend. Or both. One example where both happened was in the war in Afghanistan, when the Doctor just couldn't resist…

Dr John Watson peered out of his tent and surveyed the surroundings. There had been another attack last night, so he had had his work cut out, saving lives, performing risky surgery, the usual day at the office. He wouldn't have done it without the help of the mysterious stranger that appeared like an angel the night before, just before the attack began. He claimed to be a Doctor, and John was in no position to argue, he was just too busy. He somehow trusted this man, even though he was dressed in tweed and a frankly outrageous bow tie just wandering about in the dark. But he guessed he wasn't a Doctor. He was wrong. The mysterious tweed man had saved more lives in an hour than John had saved in a lifetime. Not that John wasn't skilled at his job; he was the best of the best. But there was something about this man that just _always_ knew what to do.

John was from a fairly well-off background: educated at Bart's, trained as an army Doctor and left before his parents could object. He had never got on much with his sister, Harry. She was having trouble, though, with her partner, Clara and drinking, and so John worried about her constantly. For the past few weeks, though, he had had no time to worry. That was all about to change.

John walked round to the side of the tent and saw the Doctor sitting there. His wild quiff was blowing gently in the soft wind. He gazed into the distance, and John stepped back in surprise, as the eyes of the young man were way beyond his years. He was staring at the eyes of an old God. When he spoke it snapped John out of his reverie.

'You OK, Doctor? Busy night last night,' the tweed God uttered.

'Uh, yeah, I guess,' John replied dazedly. 'Hang on; have you been outside all night? Do you even sleep?'

'Yes, I always sit outside at night. Failing that, the Medusa Cascade or the moons of Dotyos make a lovely spot. Sleeping? Nah, sleeping wastes time. There is so much to see, John, so much to observe that has never been observed before. Whole new galaxies, worlds to be discovered, civilisations to save, and a whole lot of running to do, and right in the middle John, it's just you and me, with our whole lives ahead of us. Me, I've people to save, things to do, battles to fight. But you, you've got your own war to win. I'm not just talking about this one we're both in the middle of, but your whole life, your human nature, your instinct. And that is beautiful. Don't lose the battle, John.'

'Uh… Ok,' John couldn't think of anything better to say. 'Do you want some coffee? I can tell one of the boys to put the kettle on.'

'Oh no, I'm quite all right. Actually, I'd better be off. Things tend to go wrong if I stay too long in any place or time. But thanks, John. For everything. And for being there.' He began to stroll of into the desert.

'Wait, Doctor! Where are you going? There's just the desert out there! You'll die! And, we need you, Doctor, you're a life saver. Doctor!?' But the ancient God made of tweed was gone. John hung his head dejectedly, knowing the strange man would die. And John needed his help.

He saw the attack before he heard it. He had often wondered what being caught unprepared would feel like. He had hoped he would go down in dignity, but he found himself rooted to the ground, completely exposing himself. If ever he wished for the sight of a tweed jacket, now would be the time. Or even that ridiculous bow tie. Or…

And with a sharp pain in his shoulder, he keeled over. His last thoughts before he blacked out were that of an ancient God trapped in a young man's body. And those old eyes, staring out into the vast desert.

_Three Earth years later, in the TARDIS_

'_Don't travel alone, Doctor'_. River's words kept circling around his broken mind. He needed help more than ever. The pain he felt was beyond unbearable. It was as if one of his hearts had literally been torn from his already wounded chest. His whole body ached with their absence. What hurt the most was that it was his fault that two more beautiful young humans were gone. How many would it take for him to stop? How many deaths before he became like the mind of a Dalek? How many broken hearts, lost lives, lost loves…? How many times would he have to die to be dead? To be gone. To have never existed. He wanted that more than ever, now. His friends kept him alive. And now they were gone. Again. And it was his fault, yet again. It always was. He knew he needed help, just to keep him going, but he had almost lost hope. He couldn't expect River to always be there, their timelines were too complicated. There was only one person he could think of that would help him, one person that he wanted to see… And he didn't even know them that well. He had only known them for one night.

_221b, Baker Street_

_London, England_

_21:41pm_

At the sound of knocking at the door, Sherlock Holmes yelled '_John! JOHN!_' When there was no reply, he groaned and moaned and heaved himself reluctantly out of the chair. John had probably gone to Dublin, again. Or something. Sherlock Holmes had always seen himself as a human, merely striving to be a God. And in his mind, he had succeeded. He just couldn't imagine being anyone else. He _certainly_ never thought he'd meet someone who was the complete opposite. Well, the great consulting detective was about to meet his match, and with it get the shock of his life…

'Hello! I'm the Doctor, can I come in? Thank you.' He barged in past Sherlock, leaving him literally lost for words, something that both intrigued and worried him, and he stood in the doorway nervously. He could hear the Doctor from down the hall. 'This is John's flat, isn't it, I mean the TARDIS definitely said it was here, and I always trust my old girl, never let me down she has, and never will, not if I can help it. Ee by by gum.' He stopped, silent, and Sherlock tensed. The Doctor turned, and walked back slowly, until he was right in front of Sherlock. He prodded him, and Sherlock tipped back, and then forward again. 'You're not John. Who are you?'

Sherlock grinned. Now it was his turn. 'Well, let's talk about you shall we, I mean you just barged into my flat without any hope of introduction so let me deduce you and I'll soon suss you out. Sooo, by your dress sense I'd say you were one of John's barmy army friends, probably on leave, before you ask you right sleeve was just screaming holiday, and you don't know me, and I don't know you, so one of his _old_ barmy army friends, and your hair, well you're younger than him but your eyes say otherwise, so, hard time at the front, the way you just strode in here talking nonsense means that you obviously haven't met me yet and don't know what I'm capable of. I just you.'

The Doctor's eyes narrowed for a split second, and Sherlock almost missed it, but not quite. Then his eyes widened into a genuinely mischievous glint and he grinned smugly and held out his hand. 'The Doctor, just the Doctor. And by the way; you're half right.'

Sherlock took it eagerly, it appeared he had met someone with vaguely the similar IQ and intelligence and understanding of the world. 'Sherlock Holmes. Only consulting detective in the world.'

The two geniuses shook hands and grinned at each other, knowing full well that the game was indeed on.

By the time John got home (just from the shops, apparently, not Dublin) the pair were in full flow, arguing to their heart's content. John stopped and dropped the shopping when he saw who Sherlock was debating with. 'Doctor?! Oh, my God what the hell are you doing here? I haven't seen you for three years, and I thought you had died!'

The Doctor grinned. 'Well that's just me, I'm afraid. Unexplained is my middle name,' when John laughed he frowned, and John silenced himself. 'No, literally, the looks I get when I fill in a form…'

Normally this would have just annoyed the hell out of John, and of Sherlock, but Sherlock was already annoyed at having been beaten at an argument for the first time in his life, and John was just too surprised to feel, or even notice, anything else.

The three were sat around the table eating an already cold Chinese takeaway. Neither the Doctor nor John were speaking to Sherlock, he had predicted the fortune cookies and had been proven wrong by the Doctor. John was really beginning to see how similar they were to each other. But he kept it to himself and just grinned to himself and sniggered smugly sometimes, knowing full well that if he even mentioned that he'd entertained the possibility; he knew that World War III might just break out, and he was anxious to watch the football. It suddenly struck him as to how insignificant he appeared to himself to be compared to these two obvious masterminds. He wondered if they even noticed him. He didn't suspect so. He knew (or thought he knew, anyway) that they were far too busy being clever to pay any sort of attention to him. Of course, this was sometimes true of Sherlock, but one thing that John was sure of was that he was like that with everyone at one time or another. What he didn't know was that the Doctor was quite the opposite, and even though he hadn't known him for too long, he was incredibly grateful to John, he believed that he had saved him from complete depression without even knowing it. In John, he had found a true friend. He thought that it was about time that he repaid his debt to him. And the Doctor was about to change John Watson's life forever. For John, Sherlock and even the Doctor himself, nothing would ever be the same again.

Now, it's a little known fact that John Watson is in fact a massive Harry Potter nerd. Always has been. He's never admitted it to anyone, of course, especially not Sherlock. But at the Doctor's unusual request he revealed all… No regrets there.


	2. John's True Fandom

**Well hello there :D My name is the Marshmellow Queen (Not really but that is my new stage name, I made it up just now, great isn't it?) Anyway I am working in collaboration with my bezzie ****PondGirl11 and together we are writing this lovely fanfiction! So anyway here's the next chapter: 2 (sorry it's a bit late I'm a filthy procrastinator, and I get distracted very, very easily)**

"So John!" The Doctor announced with a wide grin, "If you could go anywhere in the world at any point in time where would it be?"

John thought for a second, mulling over the many possibilities. He looked up after a heated discussion in his head, "The Marauders era, defiantly!"

Sherlock and the Doctor looked at him with completely baffled expressions mirrored across both of their faces.

John looked slightly amazed by their lack of knowledge, "You know... Urm... From Harry Potter?"

He offered up with a sheepish smile on his face, like he'd just been caught snooping around trying to tidy up some of Sherlock's old experiments. This had happened far too frequently to him, than you'd probably think.

"For goodness sake John! I know who the Marauders are-"

"-you do? Care to enlighten me?"

Sherlock send the Doctor a scathing look for interrupting and continued like nothing had happened.

"I know who the Marauders are! But why? Out of the times and places in the world, all the scientific discoveries that have been made, and you choose the Marauders era? That's not even a real thing!"

The Doctor looked between the fuming Sherlock and slightly annoyed John, there was something there, but he wasn't quite sure what.

"Guys?" He asked, "Still in the dark over here?" He waved his hands in front of their faces, resulting in the breaking of eye contact between the pair.

John looked up slightly dazed, his gaze focused a bit when he realised that the Doctor was expecting an answer.

"Oh! They're from Harry Potter! They're a troublesome foursome, who goes around pranking people."

"Now do you understand my pain?" Sherlock moaned to the Doctor, "Out of everything ever, he choose made up wizard 'pranksters'! Honestly!"

"I admire your sense of adventure Dr Watson!" The Doctor grinned, "So shall we get going?"

John learnt 3 years ago, to trust what the Doctor said, after all, who else could walk into a desert wasteland and still be alive three years later looking in complete health? Sherlock however was not so trusting.

"Where are we going?" he squinted suspiciously at the only person to ever beat him in an argument. "I'm not going anywhere, with someone I don't know!"

Something in John snapped.

"What the hell Sherlock?! At any point during the day, or even the night, you drag me off to any godforsaken place, and I follow you! How come when we try to go on one adventure, you decide to get all suspicious? I am going with the Doctor and you are bloody well coming along! Now grab your coat and put your shoes on!"

Sherlock looked at John in disbelief. John never shouts! John's supposed to be the calm one!

"I don't see you getting our shoes on!" John snapped, raising his eyebrow at the consultant in front of him.

"Fine, fine..." Sherlock grumbled, slightly peeved that his was being treated like a five year old.

The Doctor watched from the sidelines amusement etched all over his face, 'honestly', he thought to himself, 'they're like a married couple!'

John turned to the Doctor, still slightly miffed at his roommate, "Shall we go then?"

A massive grin appeared across the Doctors face.

"Follow me everyone!" He cheered.

After walking approximately one minute and forty three seconds, they came to a halt outside a blue police box.

Sherlock look unimpressed.

"Seriously? You made us walk all the way out here for a police box? Look, I don't care how you got it here, because this defiantly wasn't here yesterday. Hooray, a mysterious police box!"

The Doctor said not a word; he just pushed Sherlock inside the 'mysterious police box'.

Sherlock's jaw dropped, "Err... it's... b-bigger, uh, on the inside..."

John's reaction was pretty similar, apart from he didn't seem to think that words were needed, what Sherlock stammered pretty much summed it up. Unlike Sherlock, John seemed to recover reasonably quickly and soon the man face was filled with the childlike enthusiasm of a small child in a sweet shop.

"This is incredible! How is this even possible?! Is this magic? Some sort of undetectable extension charm? This is so cool!"

The Doctor just watched with an amused expression across his features. "So, Shall we go then?"

Without waiting for a reply that didn't include, "Maybe, it's a different charm..."

Ignoring the two men trying to work their way through all the mysteries of the TARDIS, he started pulling the levers and pressing the many buttons to start the dematerialisation.

Sherlock and John didn't come out of their dazes, until the Doctor said, "Well we're here, aren't you going to take a look?"

John looked up like an eager puppy. "Where are we?"

"Well you said that you wanted to go to the marauders era right?"

John's eyes filled with hope, "The Wizarding World's REAL?"

"Well, I don't know about real, but we're in the right time and place..."

"Oooh let's go and look, come on Sherlock let's go look... Sherlock?"

Sherlock was still standing in the same position as when he first walked into the TARDIS, staring at the far wall, with a scowl on his face.

John warily approached his friend, "Sherlock?" He asked softly, "You okay?"

Sherlock turned to John with a look of desperation, "It doesn't make sense, John! It's bigger on the inside! That's not scientifically possible!"

"I know Sherlock, I know, but you're judging it by the science of our day, maybe it's a new science?"

"Actually-" The Doctor started.

John cut him off with a look. Sherlock missed this exchange and looked slightly better.

"Okay, Shall we get going then?" Sherlock asked like nothing had happened. John enthusiasm was rekindled.

"Let's go!" He pushed the door open and his breath caught in his throat, neither the books nor the films could prepare him for the sight before his eyes. "_Hogwarts_!" he breathed completely enthralled. There were no words to describe the sight before him. The Doctor and Sherlock stepped out of the TARDIS after him. The Doctor let out a low whistle.

"Who are you? And what is that _thing_?"

The three men turned around warily, standing behind them, wands pointed at their necks, were four teenage boys, each swapping between glaring at the trio and looking confused at the police box behind them.

John's eyes widened and look of glee appeared on his face. "They're real!"


	3. Life At Hogwarts

**Hey, PondGirl11 here with the third chapter. I hope you all enjoyed my crazy friend's update, she's a fantastic writer but our styles are really quite different so sorry if it's confusing for you. The response has been great, so thanks very much! Also, apologies of there are any errors with any of the programmes; in our partnership I am the Whovian, she is the Harry Potter nerd and we are both Sherlockians but we do try our best to help each other when we don't understand something.**

**Disclaimer: Neither me, nor my friend, own Doctor Who, Sherlock or Harry Potter, or any of the characters in them.**

The four heroes who had inspired John for years looked puzzled.

'Real? Of course we're real, who have you been talking to? And what the _hell_ is that… _thing?_' The tallest of the four stepped forward and lowered his wand so that he was staring John in the face, eye to eye, so close John could feel his breath on his cheek. And then John let out a truly fangirl squeal. Sherlock groaned. The Doctor laughed. As soon as the madman in a box giggled, the tension immediately relaxed. John began to hyperventilate.

'I love you guys, you're amazing, I've read all the books, seen all the films, but nothing is quite as good as this, I promise you, I dream about you every day, I've been waiting for this moment for as long as I can remember…'

'John, sshh,' the Doctor purred with a grin, one slender finger on his perfect lips. John immediately stopped speaking, and looked puzzled at the Doctor. The tall wizard who had excited John earlier looked amazed.

'How did you learn how to do that?' He asked, incredulous. The Doctor grinned.

'It only works once, and only on underdeveloped life forms,' he replied with a sly smile, sensing what was going to happen next. The tall wizard immediately started asking about the TARDIS again, and, raising an eyebrow, the Doctor placed his finger on his lips, and shushed him. Just as he had predicted, the young wizard instantly fell silent. The Doctor looked at Sherlock pointedly, as if to say 'I rest my case.' John, however, looked angry that his friend had shown his hero to be underdeveloped. He cast a furious glance in the Doctor's direction, before continuing his praise of the tall wizard. The young man began to warm to these strangers, and he led them inside the castle, much to John's delight. Sherlock was wary about leaving the TARDIS where it was, but the Doctor assured him that no-one would notice it. And for some strange reason unbeknownst even to himself, Sherlock believed him.

_A few days later_

The young wizards and witches had taken to the three strange men that had appeared on their doorstep from apparently nowhere. It seemed that the Doctor had an uncanny way of getting people to trust him very quickly. Of course, when John had met Lily Potter, he had fallen to his knees and kissed her hand graciously, awed by her beauty and captured by an overwhelming desire to propose to her there and then. He held himself in, however. Wouldn't want her to think he was too forward. Poor Sherlock was having a really hard time adjusting to this new change of scenery. He bickered to his heart's content with the Doctor, and laughed with him about John, who was clearly having the time of his life, bless him. But Sherlock himself was struggling without a case; he could feel his own brain rotting every time he took a breath. He was also paranoid all the time, he could see all this magic, but he knew that _logically_ it could never be possible. But it was right there. He just couldn't handle it. The Doctor had taken to being a temporary professor at Hogwarts, something that he had wanted to do all his life (but would never have admitted it). He lectured them on all sorts, his PhDs in Medicine _and_ cheese making, and why fairyland did _not_ look like Narnia. He was having the time of his life, but it was at night when the nightmares came. He had never slept much, but now he found himself wandering about the castle at night with his head in his hands, wishing that his best friends would come back. He had never missed anyone so much.

**Sorry it's so short, but I never seem to get time to update, so I thought I'd just do a quickie.**


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